Manganese(III)-based facile synthesis of 3-cyano-4,5-dihydrofurans and 4-cyano-1,2-dioxan-3-ols using alkenes and acylacetonitrile building blocks

Article abstract of DOI:10.1055/s-1997-1282

New 3-cyano-4,5-dihydrofurans and 4-cyano-1,2-dioxan-3-ols were alternatively synthesized in good yields by the oxidation of acylacetonitrile building blocks with manganese(III) acetate in the presence of alkenes without any byproducts. The reaction at reflux temperature gave 3-cyano-4,5-dihydrofurans under an argon atmosphere, while 4-cyano-1,2-dioxan-3-ols were obtained at 23°C under an air atmosphere except for the reaction of styrene with benzoylacetonitrile which afforded 2-cyano-1,4-diphenylbutane-1,4-dione, and the reaction of 1,1-diphenylethene with 2-(2-cyano-1-oxoethyl)-5-methylfuran which yielded 2-cyano-4,4-diphenylbutanolide without any cyclic peroxides. The oxidation of benzoylacetonitrile itself at 23°C under an air atmosphere in the absence of alkene gave benzoic acid. Easy conversion of the 1,2-dioxanes to furans was demonstrated, and mechanisms for the formation of dihydrofurans and dioxanes as well as the unusual transformation to butanedione and butanolide were also discussed.